I reserve these for longer rides, where the advantage over less expensive options becomes more obvious. I like the feel of the material, and the straps and leg cuffs are very comfortable. However, what impresses me most are two things. First is the chamois, which is great because I don't notice it or think about it (unlike some others that make me squirm around or get out of the saddle every so often after 20-25 miles). I was expecting that from other reviews I've read, but what I didn't expect and really like is the slight compression the bib shorts provide. I have other bib shorts that feel snug and support my muscles, but the Aero RC bib shorts go beyond that and seemingly help my legs stay fresh longer. Size up as usual for Castelli and take them out for a very long spin. Yeah, you'll still wish they didn't cost so much, but you'll understand why they're worth it.
I have used multiple other brands bib shorts, and have had the impression that Castelli was the best, so I dove in.
The first 20-mile ride with these wasn't good. The straps rubbed the nipples raw and developed an abrasion on the left hip from the seam. I have been riding and using bib shorts for 15 years and have never had either of these issues with rides up to 200 miles in one day with the other brands.